What the Science Says

Conventional treatment for high cholesterol levels consists of therapeutic lifestyle changes (a healthy diet, weight management, and physical activity) and, if necessary, cholesterol-lowering medicine. Dietary supplements have also been studied for their possible effects on cholesterol levels.

• The use of foods containing added plant stanols or sterols is an option in conventional treatment for high cholesterol levels. Examples of these foods include orange juice with added sterols and spreads used in place of butter that contain added stanols. Stanols and sterols are also available in dietary supplements. The evidence for the effectiveness of the supplements is less extensive than the evidence for foods containing stanols or sterols, but in general, studies show that stanol or sterol supplements, taken with meals, can reduce cholesterol levels. Some foods and dietary supplements that contain stanols or sterols are permitted to carry a health claim, approved by the Food and Drug Administration (FDA), saying that they may reduce the risk of heart disease when consumed in appropriate amounts.
• Some soy products can have a small cholesterol-lowering effect. An analysis of data from 35 studies indicated that soy foods were more effective in lowering cholesterol than soy protein supplements and that isoflavones (substances in soy that have a weak estrogenic effect) did not lower cholesterol. The effect of soy is much smaller than that of cholesterol-lowering drugs.
• Studies of flaxseed preparations to lower cholesterol levels suggest possible beneficial effects for some types of flaxseed supplements, including whole flaxseed and flaxseed lignans but not flaxseed oil. The effects were stronger for women (especially postmenopausal women) than men and for people with higher initial cholesterol levels.
• A recent review of the research on garlic supplements concluded that they can lower cholesterol if taken for more than 2 months, but their effect is modest in comparison with the effects of cholesterol-lowering drugs.
• Limited evidence indicates that green tea may have a cholesterol-lowering effect. The evidence on black tea is less consistent.
• The FDA has determined that red yeast rice that contains more than trace amounts of a substance called monacolin K is an unapproved new drug and cannot be sold legally as a dietary supplement. Monacolin K is chemically identical to the cholesterol-lowering drug lovastatin, and some red yeast rice contains substantial amounts of this substance. Red yeast rice that contains monacolin K may lower blood cholesterol levels, but it can also cause the same types of side effects and drug interactions as lovastatin.
• Chromium, vitamin C, artichoke extract, the herb Hibiscus sabdariffa, coenzyme Q10, and selenium have been studied for cholesterol but have not been found to be effective. Research findings don’t show clear evidence regarding the cholesterol-lowering effects of policosanol (derived from sugar cane) and guggulipid (from the mukul mirth tree in western India).

Side Effects and Risks

• It’s important to follow your health care provider’s instructions for treating high blood cholesterol. Don’t take dietary supplements instead of your prescribed medicine. Although there’s evidence that some supplements, such as garlic and soy, can lower cholesterol, their effects are small compared to those of cholesterol-lowering medicines.
• Red yeast rice products may be contaminated with citrinin, a substance that may cause kidney damage.
• To use dietary supplements safely, read and follow the label instructions, and recognize that “natural” does not always mean “safe.” Keep in mind that dietary supplements can cause health problems if not used correctly or if used in large amounts, and some may interact with medicines. Most dietary supplements have not been tested in pregnant women, nursing mothers, or children.